Stethoscope headset

ABSTRACT

A stethoscope headset formed from a pair of arcuate housing arm members pivotably coupled at one end thereof. Each of the housing arm members is formed with a chamber adjacent said one end thereof dimensioned for receipt of an electro-acoustic transducer and a channel extending through each of said housing arm members providing communication between said chamber and the other end of said arm members. A sound conducting tube extends at least from said chamber through said channel and projects out of the other end of said arm members, an earplug being mounted on a projecting end of each of said sound conducting tubes.

United States Patent McCabe et a1.

[ Nov. 13, 1973 STETHOSCOPE HEADSET [75] Inventors: John P. McCabe,Miller Place;

Edwin Joscelyn, Commack, L. 1., both of NY.

[73] Assignee: Instrument Systems Corporation,

Jericho, L. 1., NY.

[22] Filed: Dec. 27, 1971 [21] Appl. No.: 212,262

[52] US. Cl. 179/1 ST, 179/1 G, 179/182 R [51] Int. Cl. H04r l/46, H04r5/00, H04r 1/10 [58] Field of Search 179/1 ST, 107 R, 179/114 R, 115 R,182 R, 156 R, 156 A,1G

[56] References Cited UNITED STATES PATENTS 2,849,533 8/1958 Di Mattia179/1 ST 3,671,685 6/1972 McCabe 179/156 R 2,498,960 2/1950 Mullin179/156 R 3,610,830 10/1971 Daleiden 179/1 ST 2,143,175 1/1939 Waite179/1 E 3,306,991 2/1967 Wood... 179/107 R 2,846,521 8/1958 Beidler179/182 R 3,014,998 12/1961 Simpson et al. 179/156 A PrimaryExaminer-William C. Cooper Assistant Examiner-Douglas W. OlmsAttorney-Alex Friedman et al.

[57] ABSTRACT A stethoscope headset formed from a pair of arcuatehousing arm members pivotably coupled at one end thereof. Each of thehousing arm members is formed with a chamber adjacent said one endthereof dimensioned for receipt of an electro-acoustic transducer and achannel extending through each of said housing arm members providingcommunication between said chamber and the other end of said armmembers. A sound conducting tube extends at least from said chamberthrough said channel and projects out of the other end of said armmembers, an earplug being mounted on a projecting end of eachof saidsound conducting tubes.

20 Claims, 15 Drawing Figures PATENTEUuov 13 1973 3,772,478 suwanraSTETIIOSCOPE HEADSET BACKGROUND OF THE INVENTION This invention relatesto stethoscope headsets of the type distributed by airlines to itspassengers in order to permit the private reception by each of saidusers of the available audio transmission without disturbing the otherpassengers. Such headsets are not limited to airline applications, butcan also be utilized for other purposes wherein the user requiresprivacy, or wishes to avoid disturbing other individuals in the samearea.

The three primary considerations in the design of stethoscope headsetsare the fidelity of the transmission of the sound, the comfort of theuser, and the cost of manufacture. For airline applications, suchheadsets must be lightweight and relatively inexpensive, as they arefrequently taken away by the passengers. Most modern aircraft areprovided with a jack box having a pair of air tube'outlets defining theoutlet to a pair of electroacoustic transducers. The conventionalstethoscope headsets generally consist of a pair of sound conductingtubes having a jack at one end adapted for engagement in said jackbox'MeanS are generally provided at the other end of said soundconducting tubes for forming said tubes into a stethoscope shape, theend of said tube generally being provided with earplugs for receiptwithin the ears of the user. The known stetho scope headsets have proveduncomfortable and difficult to adjust, and further, have not providedthe desired fidelity of soundtransmission.

' SUMMARY OF THE INVENTION Generally speaking, in accordance witlitheinvention, a'stethoscope headset is provided having a pair of arcuatehousing arm members and is provided coupling said arm members at one endthereof for relative pivotable displacement with the other end thereofin substantially facing relation. Each ofsaid housing arm members isformed with a chamber adjacent said one end thereof dimensioned forreceipt of an electroacoustic transducer and formed with a channelextending from said chamber through said electro-acoustic arm member tosaid other end thereof. A soundconducting tube is mounted within each ofsaid channels extending at least from said chamber and projecting fromsaid other end of said housing arm member. An earplug is mounted on theend of each of said sound conducting tubes.

Said housing arm members are each formed with an opening in the wallthereof providing communication to each of said chambers. r

The respective coupled ends of said housing arm members are formed withoverlapping facing portions,

said coupling means including ratchet means for the,

stepwise relative pivotable displacement of said arm members. Saidratchet means may include teeth projecting from the overlapping facingportions of each of said housing arm members for cooperative engagementtherebetween. Said overlapping facing portions may be biased together,and means may be provided for adjusting the force of said bias.

Said sound conducting tubes may project through said chamber and saidopening in the wall of the respective housing arm members and mayterminate in a jack member. Each of said sound conducting tubes may becoupled to the output of an electro-acoustic transducer mounted withineach of said chambers, electrical lead means being coupled to the inputto said electroacoustic transducer and may extend through said openingin the wall of each of said arm' members. The respective lead means mayterminate in a common jack member formed from a pair of plug members.Said plug members may be joined by a displaceable wall having a sinuouslateral cross-section for the relative displacement of said plugmembers.

Said overlapping facing portions of said housing arm members may definea chamber therebetween for receipt of microphone means or volume controlmeans for said electro-acoustic transducers. The end of each of saidchannels in said housing arm members adjacent said earplugs may beformed to position the projecting endof said sound conducting tubes todirect said end forwardly and downwardly relative to the head of theuser.

Said electro-acoustic transducers include a housing, an elctrmmagnetictransducer mounted within said housing, a diaphragm member positionedadjacent said electro-magnetic transducer in a sound chamber within saidhousing, said diaphragm being formed from a thin sheet of grain orientedpolyester having a metal disc mounted centrally thereon in alignmentwith the output of said electro-magnetic transducer, said diaphragmbeing formed with at least one annular convolution therein substantiallyconcentric with said metal disc. The housing is formed with a channel ofrelatively small cross-section extending from said sound chamber forproviding a controlled leak therefrom.

In another embodiment of said transducers, woofer and tweetertransducers are mounted in a housing received within each chamber, saidhousing having a sound conducting passage communicating with the outputof each of said woofer and tweeter transducers, said sound conductingtube being connected between said housing sound conducting passage, andsaid earplugs.

Accordingly, it is an object of this invention to provide a stethoscopeheadset which is comfortable and is readily adjustable, while providinghigh fidelity sound transmission.

A further object of the invention is to provide a stethoscopeheadsethousing which may accommodate electro-acoustic transducers, or,in the alternative, merely carry sound conducting tubes.

Still another-object of the arrangement according to the' invention isto provide a stethoscope headset which is inexpensive to manufacture.

Still a further object of the invention is to provide an improvedelectro-acoustic transducer.

Still other objects and advantages of the invention will in part beobvious and will in part be apparent from the specification anddrawings.

The invention accordingly comprises the features of construction,combinations of elements, and arrange ment of parts which" will beexemplified in the constructions hereinafter set forth, and the scope ofthe invention will be indicated in the claims.

BRIEF DESCRIPTION OF THE DRAWINGS For a fuller understanding of theinvention, reference is had to the following description taken inconnection with the accompanying drawings, in which:

FIG. lis a perspective view of one embodiment of the stethoscope headsetaccording to the invention mounted on a user shown in phantom lines;

FIGS. 2, 3 and 4 are cross-sectional views taken along lines 2-2, 33,and 44 respectively of FIG. v

FIG. 5 is a cross-sectional view taken along lines 55 of FIG. 2;

FIG. 6 is a fragmentary partially sectioned view of a second embodimentof the stethoscope headset according to the invention;

FIGS. 7 and 9 are cross-sectional views taken along lines 77 and 99respectively of FIG. 6;

FIG. 8 is a partially cross-sectioned view taken along lines 8-8 of FIG.7;

FIG. 10 is a fragmentary front plan view of a third embodiment of thestethoscope headset according to the invention;

FIG. 11 is a sectional view taken along lines 11-11 of FIG. 10; I

FIG. 12 is a partially sectional view of a fourth embodiment of thestethoscope headset according to the invention;

FIG. 13 is a fragmentary, partially sectioned front plan view of a fifthembodiment of the stethoscope headset according to the invention; and

FIG. 14 and 15 are sectional views taken along lines 14-l4 and 15-15respectively of FIG. 13.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to FIGS. 1-5, thestethoscope headset l0 depicted includes a pair of arcuate housing armmembers 12 and 14. Each of said housing arm members are arcuate in shapeand are joined at a pivotable coupling 16. As best shown in FIGS. 3 and4, housing arm members 12 and 14 are provided with substantially annularoverlapping end coupling portions 18 and 20 respectively. Therespectivefacing edges of said' end coupling portions are in engagement and formedwith mating teeth 22 for the stepwise relative positioning of the twohousingarm members. End coupling portions 18 and 20 are each formed withlaterally extending walls 21 and 24 respectively, bridging the innerperiphery of the respective annular coupling end portions. A centralaperture 26 is formed in wall 21, while a corresponding aligned aperture28 is formed in wall 24. A hub member 30 having a head 32 and a postportion 34 projecting axially from said head is provided. Post portion34 extends through apertures 26 and 28 and serves as the axis ofpivoting of the two housing arm members. The head 32 of said hub memberrests against wall 24 while the end of post portion 34 thereof isengaged by a spring lock disc 36. Said spring lock disc is formed with apair of spring fingers 38 which engage against post portion 34 of hubmember 30 toretain said hub member and said housing arm memberstogether. Further, said spring fingers serve to provide a resilient biastending to hold the teeth 22 in respective engagement, while permittingthe pivoting of said housing arm members. During said pivotaldisplacement, end ocupling portions 18 and 20 aredisplaced relative toeach other against the bias force of spring fingers 38 as the respectiveteeth 22 of end coupling portions 18 and 22 ride one upon the other. Ifdesired, a distinctive logo or other design may be mounted or formed onhead 32 of hub member 30.

The housing arm members are formed with a thickened region adjacent therespective end coupling portions defining chambers 40. An aperture 42 isformed in the wall of each of said housing arm members in said thickenedregion to provide access to chambers 40. As best seen in FIG. 2, therespective thickened regions of housing arm members 12 and 14 serve tolimit the pivoting of said housing arm members by engaging at the endsof the desired range of pivoting.

From the thickened region defining chambers 40, each of said housing armmembers extends in an arcuate shape to ends 44 thereof which are insubstantially facing relation. The length and curvature of each of saidhousing arm members are dimensioned so as to accommodate the head of theuser. The range of relative pivoting of the housing arm members, asdetermined by the thickened regions thereof, must be adequate 'toaccommodate users of all sizes, including children. The distance betweenend 44 and pivotable coupling 16 must be such that said pivotablecoupling does not engage against'the chin of the user at any of thepossible relative pivotable positions of said housing arm members.

Housing arm members 12 and 14 are hollow, defining a channel 46extending from chamber 40 to end 44 thereof. In the embodiment of FIGS.1 5, a sound conducting tube 48 is threaded through the aperture 42,chamber 40, and channel 46 of each of said housing arm members. An end50 of each of said soundconducting tubes projects out of end 44 of eachof said 'housing arm members. An earplug 52 is mounted on each of saidprojecting ends 50. Each of said earpieces 52 is provided with a centralbore 54 for engagement about the projecting end 50 of a sound conductingtube 48. Said earplug is provided with an annular, deformable,hemispherically shaped flange 56 for engagement in the ear of the userand for providing an air seal be tween said ear and said earplug. Inthis manner, the sound waves are transmitted along the sound conductingtube through the end of bore 54 of the earplug into the ear of the user.

As more particularly shown in FIG. 2, the end portion 44 of each of saidhousing arm members is inclined slightly downwardly towardpivotable'coupling 16. Further, as more particularly shown in FIG. 5,the end region 58 of channel 46 adjacent end 44 of each of said housingarm members is inclined in the forward direction so as to direct theprojecting end 50 of sound conducting tube 48 in said forwardlydirection relative to the user. In this manner, earplug 52 is directedslightly downwardly and forwardly, an angular orientation which isparticularly adapted for alignment with the ear canal of the user, andwhich insures a comfortable, substantially air-tight fit with the usersear.

One wall of the housing arm members according to the invention in theregion of chamber 40 and channel 46 is preferably formed of a separatecover member which permits ready access to said chamber and channel. Inthe embodiment of FIGS. 1 5, said cover member is defined by rear wall60 which is secured to the balance of the housing arm member by adhesiveor the like. The two sound conducting tubes 48 are preferably joinedtogether as a unit after they leave the respective apertures 42 in thehousing arm members. Said sound conducting tubes terminate in a jack 62adapted to plug into a jack box within which is mounted anelectroacoustic transducer. Sound waves generated by saidelectro-acoustic transducer are transmitted through jack 62, soundconducting tubes 48, and earplugs 52 to the ear of the user.

A second embodiment of the arrangement according to the invention isdepicted in FIGS. 6 8. Stethoscope headset 70 isprovided with a pair ofhousing arm members and a pivotable coupling substantially identical tothe corresponding components of the embodiment of FIGS. 1 5, and likereference numerals have been applied to like structures. Stethoscopeheadset 70 differs from stethoscoe headset 10 in that anelectro-acoustic transducer'72 is mounted within each chamber 40 inplace of sound conducting tube 48. A sound conducting tube 74 connectsthe output of electro-acoustic transducer 72 and earplug 52. Saidelectroacoustic transducer is retained in position within housing 40 byan epoxy filler 76. The electrical input to each electroacoustictransducer is taken along a cable 78, each of which contains two leads.Said cables are joined and supported in asheath 80, and terminate in ajack 82. As shown in FIG. 8, each of the cables 78 is electricallyconnected to one of the jack pins 84. The adjacent ends of each of saidjack pins and cables are mounted in an insulating body 8 6. As shown inFIG. 7, the two insulating bodies 86 are joined by a connecting wall 88having a sinuous cross-section, permitting the relative lateraldisplacement of the two insulating bodies. I

The detailed structure of electro-acoustic transducer 72 is moreparticularly shown in FIG. 9. Said transducer is provided with a housingconsisting of a cover portion 90 and a base portion 92. Cover portion 90is formed with an annular axially extending flange 94 dimensioned forreceipt within base portion 92 and formed with an annular rib-96. Theinner surface of base portion 92 is formed with a corresponding annulargroove 98 for receiving rib 96 to maintain said cover and base portionsof the housing in looking engagement. The base portion of the housing isformed with an axially aligned stub 100 having a bore 102 therethroughproviding communication-to the inside of said housing. The end ofsoundconducting tube 74 is received around stub 100 for the transmission ofsound waves thereto. Mounted within the housing is an electromagnetictransducer 104 which serves to convert theelctrical audio signal to theoscillations of amagnetic field aligned with pole piece 106. Suchelectroacoustic transducer, to which cable 78 is connected, is

held within the housing by means of a positioning ring 108. Disc-shapeddiaphragm 110 is also positioned and held by positioning ring 108, saiddiaphragm being positioned intermediate pole piece 106 and bore 102 ofstub 100. Said diaphragm is preferably formed of a grain orientedpolyester such as Mylar and has a metal disc 112 mounted centrallythereon in facing relation to pole piece 106. Diaphragm 110 is formedwith two annular convolutions 114 concentric with an extending about themetal disc 112.-The variations in the magnetic field produced inresponse to the input audio signal causes the vibration of diaphragm 110due to the cooperation of pole piece 106 and metal disc 112, to producethe sound waves transmitted along sound conducting tube 74 to the ear ofthe user.

Diaphragm 110 is firmly clamped along its periphery against base portion92 by positioningring'108, and is held in place by the engagement ofsaid positioning ring by the end of the annular flange 94 of coverportion 90. The relative spacing between diaphragm 110 and pole piece'106 is maintained by the engagement of the electro-magnetic transducer104 against an annular flange 116 on positioning ring 108. A portion ofsaid positioning ring is provided with an axially extending slot 118which provides communication between the region intermediate thediaphragm and the electro-magnetic transducer and the regionintermediate said electromagnetic transducer and cover portion 90. Thisslot, which is of relatively small dimensions provides a controlled leakin the air chamber of the diaphragm which serves to improve the lowfrequency response of the electro-acoustic transducer. It is noted thatthe convolutions 114 in diaphragm also serves to improve the frequencyresponseof the transducer. It has also been found that the innerdiameter of sound conducting tube 74 contributes to the frequencyresponse of the arrangement. Thus,it has been found that optimum resultsare obtained where said inner diameter lies in the range of 0.075 0.11inch.

Because the stethoscope headset embodiment of FIGS. 6 8 utilizes asubstantially shorter sound conducting tube, and therefore involvessubstantially lower transmission losses than the embodiment of FIGS. 15, the former embodiment provides greater fidelity in soundtransmission, while still providing a relatively inexpensive and compactstethoscope headset.

Referring now to FIGS. 10 and 11, a further embodiment of thearrangement according to the invention is depicted, wherein a microphoneis mounted in the pivotable coupling 16.. Except for the detailedstructure of the pivotable coupling, the embodiment of FIGS. 10 and 11is substantially identical to the embodiment of FIGS. 1 5 or theembodiment of FIGS. 6 8. Pivotable coupling 16' incorporates an endcoupling portion 18' forming a part of housing arm memberv12' and an endcoupling portion 20 forming a part of housing arm member 14'. Endcoupling portion 18 is substantially identical to end coupling portion18 of the embodiment of FIGS. 1 5, being formed with the teeth 22', inmeshing engagement with the corresponding teeth on end coupling portion20' and wall 21' having aperture 26 therethrough. End coupling portion20' is formed with a transverse wall 24 but the aperture 28' therein isof substantially larger diameter in order to accommodate the housing 120of a microphone 122. Said microphone is received within the cavity 124defined between walls 21' and 24'. Housing 120 is formed with aperipheral flange 126 which engages against the outer surface of wall24. Said housing is also provided with a stub 128 which projects throughaperture 26' and is engaged by the spring fingers 38 of spring lock disc36', in much the same manner as post portion 34 is engaged by thecorresponding structure in stethoscope headset 10. The electrical leads130 providing the output of microphone 122 extend through a central bore132 in stub 128 and would be coupled by a suitable jack to any desiredinput. The microphone is positioned immediately below the chin of theuser, at which position it can receive and transmit conversations ofsaid user.

Still another embodiment of the pivotable coupling is depicted in FIG.12. In said embodiment, pivotable coupling 16" has a potentiometermounted in the cavity defined between walls 21" and 24" of end couplingportions 18" and 20" respectively. Potentiometer 140 is provided with apair of separate controls 142 and 144 controlling separate potentiometerwindings. Each of said windings is provided with a separate set of leadswhich extend through an aperture in housing 146 of said potentiometer.Only one of said set of leads 148 and one of said apertures 150 aredepicted in FIG. 12, the other of said set of leads being on the opposedside of said potentiometer. Suitable slots and apertures (not shown)would be formed in the annular end coupling portions 18" and 20", and inthe wall of the corresponding housing arm members providing access forleads 146 into the respective chambers 40. In this manner, each of thepotentiometer winds would be connected to one of the electro-acoustictransducers 72 for the separate control of the volume thereof.

Housing 146 is provided with an annular flange 152 which engages againstthe outer surface of wall 24", and is provided with a stub 154 whichextends into aperture 26 in wall 21". Unlike the above-describedembodiments, potentiometer 140 is held in place by means of a bolt 156threadable received in stub 154 and serving to engage and bias springwasher 158 against wall 21". This mounting method could be utilized inany of the embodiments of FIGS. 1 11.

Referring now to FIGS. 13-15, a further embodiment of the arrangementaccording to the invention is depicted, wherein stethoscope headset 170is provided with a pair of housing arm members 162 and 164 and apivotable coupling 166 substantially identical to the correspondingcomponents of the embodiment of FIGS. 1 5. Stethoscope headset 160differs from stethoscope headsets land 70 in that an electroacoustictransducerassembly 168 is received within the chamber 170 defined byeachof said housing arm members. Transducer assembly 168 consists of ahousing 172 formed with a pair. of cylindrical recesses 174 and 176within which are mounted a woofer electr0- I acoustic transducer 178 anda tweeter electro-acoustic transducer 180 respectively.

Housing 172 is formed with a sound conducting passage 182 havinglaterally extending branches 184 and 186 providing communication tocylindrical recessess 174 and 176 respectively. The outputs 188 and 190of transducers 178 and 180 respectively are positioned to apply theacoustic output signal of said transducers to said branches, andtherefore to sound conducting channel 182. Said sound conducting channelis formed with a widened region 192 defining the outlet end thereof, anddimensioned to receive 'one'end of a sound conducting tube 194, theother end of said sound conducting tube being connected to an earp'lug(not shown).

A further transverse branch 196 extends from housing 17 2, terminatingin end wall 197. Branch 196 serves as a tuning port for smoothing theresponse versus frequency characteristics of the combined'outputs of thewoofer and tweeter transducers. In one embodiment, said tuning port istuned for about 7,000 Hz. By careful selection of the woofer and tweetertransducers and design of the tuning port, the desired characteristicsof the signal applied to sound conducting tube 194 can be achieved. Suchdesirable characteristics require accentuating the low frequencies, sothat, starting at about 200 Hz, the response vs. frequencycharacteristic rolls off at about 3 to 6 db per octive. To this end, therelative impedances of the woofer and tweeter are matched, taking intoconsideration the relative efficiencies of said woofer and tweetertransducers, so that the woofer predominates, and so that thecombination of the woofer and tweeter have a suitable input impedance.The electrical input to said transducers is obtained from cable 198which passes through aperture 200 in housing arm member 162. Cable 198consists of a lead 202 which is connected to input terminal 204 ofwoofer transducer 178 and lead 206 connected to a terminal 208 of apotentiometer 210. Said potentiometer serves as a volume control, and ismounted within chamber and formed with a rotatable control shaft 212projecting through an operture 214 in housing arm member 162. A knob 216is mounted on the end of control shaft 212 to permit the adjustment andsetting of potentiometer 210. The woofer and tweeter transducers 178 andare connected in parallel, with lead 218 connecting terminal 204 oftransducer 178 with terminal 220 of transducer 180, and lead 222connectingterminal 224 of transducer 178 with terminal 226. Finally, alead 228 interconnects terminal 226 of transducer 180 with terminal 230of potentiometer 210.

As more particularly shown in FIG. 15, still a further transverse branch232 coupling end chamber 170 in the region of opening 200 in housing armmember 162 is also provided. In the embodiment depicted in the drawings,said further branch 232 is blocked by, for example, an epoxy 234. Whereit is desired to mix the output of the left and right transducerassemblies according to the invention, one of said assemblies beingmounted in each of the housing arm members 162 and 164, branch 232 couldbe left open, and a sound con ducting tube could be provided couplingthe branch 232 of each of the transducer assemblies 168, said soundconducting tubes extending through the respective openings 200 in thehousing arm members 162 and 164. Such an arrangement would provide notonly for the mixing of the signals directed to the left and right earsof the user, but also would provide for a delay in one of the mixedsignals which creates a three dimensional stereophonic effect.

Means, such as projections and/or epoxy could be provided forpositioning. and retaining each transducer assembly 168 andpotentiometer 210.

It will thus be seen that the objects set forth above, and those madeapparent from the preceding description, are efficiently attained and,since certain changes may be made in the above constructions withoutdeparting from the spirit and scope of the invention, it is intendedthat all matter contained in the above description or shown in theaccompanying drawings shall be interpreted as illustrative and not in alimiting sense.

It is also to be understood that the following claims are intended tocover all of the generic and specific features of the invention hereindescribed, and all statements of the scope of the invention which, as amatter of language, might be said to fall therebetween.

.What is claimed is:

l. A stethoscope headset comprising a pair of arcuate rigid housing armmembers, each of said housing arms members being formed at one endthereof with an and coupling portion positioned in overlapping facingrelation with the end coupling portion of the other of said housing armmembers, each of said housing ann members being formed with a thickenedregion adjacent said end coupling portion defining a chamber, a wall ofsaid thickened region being formed with an aperture therethroughproviding access to said chamber from outside of said housing armmembers, each of said housing arm members being further formed with achannel therethrough extending from said chamber to the other endthereof; means coupling the respective end coupling portions of saidhousing arm members for relative pivotable displacement with said otherend of said housing arm members in substantial facing relation', saidcoupling means including ratchet means mounted for cooperativeengagement on each of said end coupling portions for the stepwiserelative pivotable displacement of said arm members; a flexiblesound-conducting tube mounted within each of said channels extendingfrom at least said chamber and projecting from said other end of saidhousing arm member, each of said housing arm members being formed sothat the regions of each of said channels adjacent the ends of saidhousing arm members spaced from said end coupling portions are shaped soas to incline the projecting ends of said sound conducting tubesforwardly from the plane of the headset relative to the head of the userof said headset; and earplug means mounted on said projecting end ofeach of said sound conducting tubes.

2. A stethoscope headset as recited in claim 1, wherein said ratchetmeans includes teeth projecting from each of said overlapping facingportions and means for biasing said teeth in cooperative engagement.

3. A stethoscope headset as recited in claim 1, wherein the ends of eachof said housing arm members spaced from said end coupling portions areinclined toward said end coupling portions so that said projecting endsof said sound conducting tubes incline downwardly and forwardly relativeto the head of the user of said headset.

4. A stethoscope headset as recited in claim 1, wherein each of saidsound conducting tubes extend through said chamber and said aperture insaid thickened region of its respective housing arm member; and jackmeans coupled to thevrespective ends of said sound conducting tubesprojecting outside of said housing arm members through said apertures.

5. A stethoscope headset as recited in claim 1, including anelectro-acoustic transducer means positioned in each of said chambers,said sound conducting tube being coupled to the output of saidtransducer means; and lead means coupled to the input of 'saidtransducer means and extending out of each said housing arm memberthrough said aperture in said thickened region thereof.

6. A stethoscope headset as recited in claim 5, wherein said soundconducting tube is formed with an inner diameter of about 0.075 0.11inch.

7. A stethoscope headset as recited in claim 5, including jack meanscoupled to the lead means associated with each of said transducers, saidjack means including a pair of jack pins, one of said pins being coupledto each of said lead means, insulating body means encapsulating adjacentportions of each of said jack pins and lead means, and connecting wallmeans, said connecting wall means having a sinuous transversecross-section for permitting the relative transverse displacement ofsaid pin jacks.

8. A stethoscope headset as recited in claim 5, wherein saidelectro-acoustic transducer means includes a housing having an aperturetherethrough defining said transducer output; an electromagnetictransducer mounted within said housing and having an axial pole piecedefining the output thereof; a diaphragm member positioned intermediatesaid transducer output and said electromagnetic transducer, saiddiaphragm member being formed from a thin sheet of grain orientedpolyester having a thin metal disc mounted centrally thereon insubstantial alignment with said pole piece, said diaphragm member havingat least one annular ridge formed by said thin sheet substantiallyconcentric with said metal disc; and positioning ring means mountedwithin said housing for positioning said diaphragm member andelectro-magnetic transducer in spaced relation within said housing.

9. A stethoscope headset as recited in claim 8, wherein said positioningring means is formed with a channel of relatively small cross-sectionextending from the region intermediate said electro-magnetic transducerand said diaphragm member to the region within said housing on theopposed side of said electromagnetic transducer for providing acontrolled leak from said first-mentioned region.

10. A stethoscope headset as recited in claim 8, wherein said diaphragmmember is formed with two of said annular concentric ridges.

11. A stethoscope headset as recited in claim 5, wherein saidelectro-acoustic transducer means includes a housing formed with asound-conducting passage extending to the outside of said housing anddefining thereat the output of said transducer means; a wooferelectro-acoustic transducer mountedin said housing and having an outletpositioned for applying an acoustic signal to said sound-conductingpassage; a tweeter electro-acoustic transducer mounted within saidhousing and having an output positioned for application of an acousticsignal to said sound-conducting passage; said lead means connecting saidwoofer and tweeter electro-acoustic transducers in parallel at theirrespective inputs.

12. A stethoscope headset as recited in claim 11, wherein said housingis formed with a transverse bore providing communication between saidsoundconducting passage and the outside of said housing, said bore beingdimensioned to define a tuning port for substantially smoothing theresponse versus frequency characteristics of said transducer means. I

13. A stethoscope headset as recited in claim 12, wherein saidtransverse bore, and said woofer and tweeter electro-acoustictransducers being selected so as to provide a respeonse versus frequencycharacteristics which rolls off at about 3 to 6 db per octive from about200 Hz 14. A stehtoscope headset as recited in claim 11, wherein saidhousing is formed with a bore interconnecting said soundconductingpassage and the outside of said housing, said bore being adapted toreceive a sound-conducting tube for the application of a further audiosignal to said transducer means.

15. A stethoscope headset as recited in claim 5, including potentiometermeans mounted within each of said chambers, each of said housing armmembers being formed with a further aperture therethrough in the regionof its respective chamber, said potentiometer means being formed withmanual adjusting means extending through said further aperture, saidlead means coupling said transducer means and said potentiometer meansin series for the manual adjustment of the volume of the audio output ofsaid transducer means.

16. A stethoscope headset as recited in claim 1, wherein one of said endcoupling portions is formed with a first transverse wall and the otherof said end coupling portions is formed with a second transverse wall inoverlapping spaced relation to said first transverse wall, said firsttransverse wall having an aperture therethrough; and includingmicrophone means positioned in the space between said first and secondtransverse walls and having an input face projecting through saidaperture in said first transverse wall.

17. A stethoscope headset as recited in claim 16, wherein said secondtransverse wall is formed with an aperture therethrough, said microphonemeans having a housing formed with a radial flange dimensioned forengagement against the outer surface of said first transverse wall, saidmicrophone means housing also being formed with a projecting stubextending'through said aperture in said second transverse wall, saidcoupling means including means for engaging said stub and said secondtransverse wall for retaining said housing arm members in pivotablecoupling with said microphone means housing serving as the axis ofpivoting thereof.

18. A stethoscope headset as recited in claim 5, wherein one of said endcoupling portions is formed with a first transverse wall having anaperture therethrough, the other of said end coupling portions beingformed with a second transverse wall in spaced overlapping relation tosaid first transverse wall; and including potentiometer means positionedwithin the space between said first and second transverse walls andhaving control means projecting through said aperture in said firsttransverse wall; and lead means operatively coupling said potentiometermeans with each of said electro-acoustic transducers for the control ofthe signal applied thereto.

19. A stethoscope headset as recited in claim 18, wherein saidpotentiometer means includes two separate potentiometer winding means,said control means including two separate controls, one of said separatecontrols being operatively coupled to each of said potentiometer windingmeans.

20. A stethoscope headset as recited in claim 18, wherein said secondtransverse wall is formed with an aperture therethrough, saidpotentiometer means including a housing formed with a radial flangepositioned for engagement with the outer surface of said firsttransverse wall, said potentiometer means housing being formed with aprojecting stub extending through said aperture in said secondtransverse wall, said coupling means including means for engaging saidstub and said second transverse wall for coupling said housing armmembers together with said potentiometer means housing defining the axisof pivoting thereof.

1. A stethoscope headset comprising a pair of arcuate rigid housing armmembers, each of said housing arms members being formed at one endthereof with an end coupling portion positioned in overlapping facingrelation with the end coupling portion of the other of said housing armmembers, each of said housing arm members being formed with a thickenedregion adjacent said end coupling portion defining a chamber, a wall ofsaid thickened region being formed with an aperture therethroughproviding access to said chamber from outside of said housing armmembers, each of said housing arm members being further formed with achannel therethrough extending from said chamber to the other endthereof; means coupling the respective end coupling portions of saidhousing arm members for relative pivotable displacement with said otherend of said housing arm members in substantial facing relation; saidcoupling means including ratchet means mounted for cooperativeengagement on each of said end coupling portions for the stepwiserelative pivotable displacement of said arm members; a flexiblesound-conducting tube mounted within each of said channels extendingfrom at least said chamber and projecting from said other end of saidhousing arm member, each of said housing arm members being formed sothat the regions of each of said channels adjacent the ends of saidhousing arm members spaced from said end coupling portions are shaped soas to incline the projecting ends of said sound conducting tubesforwardly from the plane of the headset relative to the head of the userof said headset; and earplug means mounted on said projecting end ofeach of said sound conducting tubes.
 2. A stethoscope headset as recitedin claim 1, wherein said ratchet means includes teeth projecting fromeach of said overlapping facing portions and means for biasing saidteeth in cooperative engagement.
 3. A stethoscope headset as recited inclaim 1, wherein the ends of each of said housing arm members spacedfrom said end coupling portions are inclined toward said end couplingportions so that said projecting ends of said sound conducting tubesincline downwardly and forwardly relative to the head of the user ofsaid headset.
 4. A stethoscope headset as recited in claim 1, whereineach of said sound conducting tubes extend through said chamber and saidaperture in said thickened region of its respective housing arm member;and jack means coupled to the respective ends of said sound conductingtubes projecting outside of said housing arm members through saidapertures.
 5. A stethoscope headset as recited in claim 1, including anelectro-acoustic transducer means positioned in each of said chambers,said sound conducting tube being coupled to the output of saidtransducer means; and lead means coupled to the input of said transducermeans and extending out of each said housing arm member through saidaperture in said thickened region thereof.
 6. A stethoscope headset asrecited in claim 5, wherein said sound conducting tube is formed with aninner diameter of about 0.075 - 0.11 inch.
 7. A stethoscope headset asrecited in claim 5, including jack means coupled to the lead meansassociated with each of said transducers, said jack means including apair of jack pins, one of said pins being coupled to each of said leadmeans, insulating body means encapsulating adjacent portions of each ofsaid jack pins and lead means, and connecting wall means, saidconnecting wall means having a sinuous transverse cross-section forpermitting the relative transverse displacement of said pin jacks.
 8. Astethoscope headset as recited in claim 5, wherein said electro-acoustictransducer means includes a housing having an aperture therethroughdefining said transducer output; an electromagnetic transducer mountedwithin said housing and having an axial pole piece definIng the outputthereof; a diaphragm member positioned intermediate said transduceroutput and said electromagnetic transducer, said diaphragm member beingformed from a thin sheet of grain oriented polyester having a thin metaldisc mounted centrally thereon in substantial alignment with said polepiece, said diaphragm member having at least one annular ridge formed bysaid thin sheet substantially concentric with said metal disc; andpositioning ring means mounted within said housing for positioning saiddiaphragm member and electro-magnetic transducer in spaced relationwithin said housing.
 9. A stethoscope headset as recited in claim 8,wherein said positioning ring means is formed with a channel ofrelatively small cross-section extending from the region intermediatesaid electro-magnetic transducer and said diaphragm member to the regionwithin said housing on the opposed side of said electro-magnetictransducer for providing a controlled leak from said first-mentionedregion.
 10. A stethoscope headset as recited in claim 8, wherein saiddiaphragm member is formed with two of said annular concentric ridges.11. A stethoscope headset as recited in claim 5, wherein saidelectro-acoustic transducer means includes a housing formed with asound-conducting passage extending to the outside of said housing anddefining thereat the output of said transducer means; a wooferelectro-acoustic transducer mounted in said housing and having an outletpositioned for applying an acoustic signal to said sound-conductingpassage; a tweeter electro-acoustic transducer mounted within saidhousing and having an output positioned for application of an acousticsignal to said sound-conducting passage; said lead means connecting saidwoofer and tweeter electro-acoustic transducers in parallel at theirrespective inputs.
 12. A stethoscope headset as recited in claim 11,wherein said housing is formed with a transverse bore providingcommunication between said sound-conducting passage and the outside ofsaid housing, said bore being dimensioned to define a tuning port forsubstantially smoothing the response versus frequency characteristics ofsaid transducer means.
 13. A stethoscope headset as recited in claim 12,wherein said transverse bore, and said woofer and tweeterelectro-acoustic transducers being selected so as to provide a respeonseversus frequency characteristics which rolls off at about 3 to 6 db peroctive from about 200 Hz.
 14. A stehtoscope headset as recited in claim11, wherein said housing is formed with a bore interconnecting saidsoundconducting passage and the outside of said housing, said bore beingadapted to receive a sound-conducting tube for the application of afurther audio signal to said transducer means.
 15. A stethoscope headsetas recited in claim 5, including potentiometer means mounted within eachof said chambers, each of said housing arm members being formed with afurther aperture therethrough in the region of its respective chamber,said potentiometer means being formed with manual adjusting meansextending through said further aperture, said lead means coupling saidtransducer means and said potentiometer means in series for the manualadjustment of the volume of the audio output of said transducer means.16. A stethoscope headset as recited in claim 1, wherein one of said endcoupling portions is formed with a first transverse wall and the otherof said end coupling portions is formed with a second transverse wall inoverlapping spaced relation to said first transverse wall, said firsttransverse wall having an aperture therethrough; and includingmicrophone means positioned in the space between said first and secondtransverse walls and having an input face projecting through saidaperture in said first transverse wall.
 17. A stethoscope headset asrecited in claim 16, wherein said second transverse wall is formed withan aperture therethrough, said microphone means having a housing formedwith a radial flanGe dimensioned for engagement against the outersurface of said first transverse wall, said microphone means housingalso being formed with a projecting stub extending through said aperturein said second transverse wall, said coupling means including means forengaging said stub and said second transverse wall for retaining saidhousing arm members in pivotable coupling with said microphone meanshousing serving as the axis of pivoting thereof.
 18. A stethoscopeheadset as recited in claim 5, wherein one of said end coupling portionsis formed with a first transverse wall having an aperture therethrough,the other of said end coupling portions being formed with a secondtransverse wall in spaced overlapping relation to said first transversewall; and including potentiometer means positioned within the spacebetween said first and second transverse walls and having control meansprojecting through said aperture in said first transverse wall; and leadmeans operatively coupling said potentiometer means with each of saidelectro-acoustic transducers for the control of the signal appliedthereto.
 19. A stethoscope headset as recited in claim 18, wherein saidpotentiometer means includes two separate potentiometer winding means,said control means including two separate controls, one of said separatecontrols being operatively coupled to each of said potentiometer windingmeans.
 20. A stethoscope headset as recited in claim 18, wherein saidsecond transverse wall is formed with an aperture therethrough, saidpotentiometer means including a housing formed with a radial flangepositioned for engagement with the outer surface of said firsttransverse wall, said potentiometer means housing being formed with aprojecting stub extending through said aperture in said secondtransverse wall, said coupling means including means for engaging saidstub and said second transverse wall for coupling said housing armmembers together with said potentiometer means housing defining the axisof pivoting thereof.